Display device

ABSTRACT

A display device capable of emitting sufficient fluorescence is provided without an increase in the thickness of the liquid crystal layer. The device includes: a fluorescent emission layer ( 23 ) having fluorescent pigment molecules that absorb light to emit fluorescence; and a liquid crystal layer ( 4 ) capable of switching between a transparent state and a scattering state. The fluorescent pigment molecules are dichroic fluorescent pigment molecules ( 23   a ) with different emission intensities depending on the direction of emission. The dichroic fluorescent pigment molecules ( 23   a ) in the fluorescent emission layer ( 23 ) are oriented so as to have transition dipole moments with the same direction.

This application is a continuation of U.S. patent application Ser. No.13/695,579 filed Oct. 31, 2012, which is the U.S. national phase ofInternational Application No. PCT/JP2011/059542 filed 18 Apr. 2011 whichdesignated the U.S. and claims priority to JP 2010-103397 filed 28 Apr.2010, the entire contents of each of which are hereby incorporated byreference

TECHNICAL FIELD

The present invention relates to a display device capable of emittingfluorescence depending on orientation of liquid crystal in the liquidcrystal layer.

BACKGROUND ART

Display devices capable of emitting fluorescence while controllingorientation of liquid crystal are known. In such a display device, asdisclosed in JP-Hei 5(1993)-173116 A, for example, pigment is added tothe liquid crystal layer and the orientation of the pigment is changeddepending on the movement of liquid crystal in the liquid crystal layer.For example, when no voltage is applied and the liquid crystal is in arandom state, the pigment is also in a random state such that the colorof the liquid crystal layer is that of the pigment. When a voltage isapplied and the liquid crystal is in an oriented state, the pigment isalso in an oriented state such that the liquid crystal layer istransparent. JP-Hei 5-173116 A also describes adding fluorescentmaterial to the liquid crystal layer to increase the intensity of colorof the pigment.

DISCLOSURE OF THE INVENTION

In an arrangement with fluorescent material added to the liquid crystallayer, as disclosed in JP-Hei 5-173116 A, it is preferable to use asignificant amount of fluorescent material in the liquid crystal panelin order to allow the display panel to emit bright fluorescence.However, it is difficult to allow the display panel to emit clearfluorescence under a bright environment since the solubility offluorescent material in liquid crystal is limited.

To solve this problem, the thickness of the liquid crystal layer may beincreased to allow a sufficient amount of fluorescent material to beadded to the liquid crystal layer. However, this requires increasedvoltage applied to the liquid crystal layer and is thus impractical.

An object of the present invention is to provide a display devicecapable of emitting sufficient fluorescence without increasing thethickness of the liquid crystal layer.

A display device according to an aspect of the present inventionincludes: a fluorescent emission layer having fluorescent pigmentmolecules that absorb light to emit fluorescence; and a liquid crystallayer capable of switching between a transparent state and a scatteringstate, wherein the fluorescent pigment molecules are dichroicfluorescent pigment molecules with different emission intensitiesdepending on a direction of emission, and the dichroic fluorescentpigment molecules in the fluorescent emission layer are oriented so asto have transition dipole moments with the same direction.

The present invention provides a display device capable of emittingsufficient fluorescence without increasing the thickness of the liquidcrystal layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a display panel of adisplay device according to a first embodiment.

FIG. 2 illustrates how light emitted by dichroic fluorescent pigment isreflected within the display panel when the liquid crystal layer is inthe transparent state in the display panel of the display deviceaccording to the first embodiment.

FIG. 3 illustrates how light emitted by dichroic fluorescent pigment isscattered within the display panel when the liquid crystal layer is inthe scattering state in the display panel of the display deviceaccording to the first embodiment.

FIG. 4 is a schematic cross-sectional view of a display panel of adisplay device according to Variation 1 of the first embodiment.

FIG. 5 is a schematic cross-sectional view of a display panel of adisplay device according to Variation 2 of the first embodiment.

FIG. 6 is a schematic cross-sectional view of a display panel of adisplay device according to a second embodiment.

FIG. 7 is a schematic cross-sectional view of a display panel of adisplay device according to a third embodiment.

FIG. 8 is a schematic cross-sectional view where features of the displaypanel of the display device according to the third embodiment areapplied to the display panel of the display device according to thesecond embodiment.

FIG. 9 is a schematic cross-sectional view of a display panel of adisplay device according to a variation of the third embodiment.

FIG. 10 is a schematic cross-sectional view of a display panel of adisplay device according to a fourth embodiment.

FIG. 11 is a schematic view of a display device according to a fifthembodiment.

FIG. 12 is a cross section taken on line XII-XII of FIG. 11.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

A display device according to an embodiment of the present inventionincludes: a fluorescent emission layer having fluorescent pigmentmolecules that absorb light to emit fluorescence; and a liquid crystallayer capable of switching between a transparent state and a scatteringstate, wherein the fluorescent pigment molecules are dichroicfluorescent pigment molecules with different emission intensitiesdepending on a direction of emission, and the dichroic fluorescentpigment molecules in the fluorescent emission layer are oriented so asto have transition dipole moments with the same direction (firstarrangement).

In the above arrangement, the liquid crystal layer and the fluorescentemission layer containing fluorescent pigment are separated from eachother. As such, fluorescent pigment need not be dissolved in the liquidcrystal layer, eliminating the necessity to increase the thickness ofthe liquid crystal layer so as to allow a significant amount offluorescent pigment to be added to the liquid crystal layer. In order toprovide sufficient fluorescence in the above arrangement, the thicknessof the fluorescent emission layer may be suitably increased. Thus, theabove arrangement allows the amount of emission to be varied withoutchanging the voltage applied to the liquid crystal layer.

Moreover, the fluorescent pigment molecules in the fluorescent emissionlayer are dichroic fluorescent pigment molecules with different emissionintensities depending on the direction of emission. Thus, as themolecules have transition dipole moments with the same direction, thedichroic fluorescent pigment molecules are capable of emitting light inthe same direction, allowing the fluorescent emission layer to emitlight with increased brightness or improved contrast.

Furthermore, in the above arrangement, refraction conditions forintensive light emitted from dichroic fluorescent pigment molecules maybe changed within the display device to change the intensity offluorescent light. That is, liquid crystal in the liquid crystal layermay be controlled to cause bright light emitted from dichroicfluorescent pigment molecules to be scattered by liquid crystal and thento be let out, or to be totally reflected in the display device and tobe trapped within the display device. Thus, liquid crystal within theliquid crystal layer may be controlled to change conditions offluorescent light of the display device.

In the first arrangement above, it is preferable that the dichroicfluorescent pigment molecules in the fluorescent emission layer areoriented such that the direction of the transition dipole moments is inagreement with a thickness direction of the fluorescent emission layer(second arrangement).

A dichroic fluorescent pigment molecule has the property of emitting, ina direction perpendicular to that of the transition dipole moments,light oscillating in a direction parallel to that of the transitiondipole moments. As such, when the liquid crystal in the liquid crystallayer is in the scattering state, the above arrangement causes lightemitted in a direction perpendicular to that of the transition dipolemoments of the dichroic fluorescent pigment molecules to be scattered bythe liquid crystal and to be let out. When the liquid crystal in theliquid crystal layer is in the transparent state, light emitted in adirection perpendicular to that of the transition dipole moments of thedichroic fluorescent pigment molecules is totally reflected repeatedlywithin a transparent layer containing, for example, a liquid crystallayer, a fluorescent emission layer and other layers. Thus, in the abovearrangement, the liquid crystal in the liquid crystal layer may becontrolled to control fluorescent light from the display device.

It should be noted that “the direction of the transition dipole momentsof the dichroic fluorescent pigment molecules is in agreement with athickness direction of the fluorescent emission layer” includes exactagreement as well as the direction of their transition dipole momentsbeing at an angle relative to the thickness direction.

In the first or second arrangement above, it is preferable that anultraviolet absorbing layer that absorbs ultraviolet light is providedbetween the fluorescent emission layer and the liquid crystal layer(third arrangement).

Thus, the fluorescent emission layer is directly illuminated withultraviolet light such that the dichroic fluorescent pigment moleculesin the fluorescent emission layer can efficiently absorb ultravioletlight and emit light. Ultraviolet light that has not been absorbed bythe dichroic fluorescent pigment molecules in the fluorescent emissionlayer is absorbed by the ultraviolet absorbing layer such that it doesnot reach the liquid crystal layer. Thus, dichroic fluorescent pigmentmolecules can emit brighter light using ultraviolet light and the liquidcrystal layer can be protected from ultraviolet light.

In any one of the first to third arrangements, above it is preferablethat the fluorescent emission layer includes a light emitting layerformed as a sheet and a bonding layer that bonds the light emittinglayer to a bonded portion, and an ultraviolet absorbing agent is addedto at least one of the light emitting layer and the bonding layer(fourth arrangement).

As the fluorescent emission layer is formed as a sheet, a fluorescentemission layer may be easily provided on the display device by attachingthe sheet-like fluorescent emission layer to the substrate or the like.Moreover, the ultraviolet absorbing agent added to at least one of thelight emitting and bonding layers will prevent ultraviolet light fromreaching the liquid crystal layer.

In any one of the first to fourth arrangements above, it is preferablethat an electrode is only provided on one side of the liquid crystallayer as viewed in a thickness direction thereof, and the electrode is apectinate electrode having comb-teeth shaped portions (fiftharrangement).

Thus, an electric field can be generated around the pectinate electrode,eliminating the necessity to laminate a common electrode in a thicknessdirection of the liquid crystal layer. This prevents light reflection orabsorption that would occur if a transparent common electrode of indiumtin oxide (ITO) or the like were formed, thereby allowing light to beefficiently introduced into the liquid crystal layer.

In any one of the first to fifth arrangements, it is preferable that alight guide plate for introducing light from a light source into thefluorescent emission layer is provided on the fluorescent emission layer(sixth arrangement).

Thus, light from the light source is repeatedly reflected in the lightguide plate and enters the fluorescent emission layer. In this case,light enters at an angle relative to a thickness direction of thefluorescent emission layer, such that light enters the dichroicfluorescent pigment molecules in the fluorescent emission layer in adirection perpendicular to that of the transition dipole moments. Assuch, the properties of dichroic fluorescent pigment molecules cause thedichroic fluorescent pigment molecules to emit brighter light. Thus, inthe arrangement above, the dichroic fluorescent pigment molecules canemit brighter fluorescence.

In any one of the first to sixth arrangements above, it is preferablethat a photovoltaic unit that receives light emitted from dichroicfluorescent pigment molecules in the fluorescent emission layer andgenerates electricity is provided outside the fluorescent emission layeras viewed in a planar direction (seventh arrangement).

Thus, light emitted from dichroic fluorescent pigment molecules in thefluorescent emission layer can be converted into electricity by thephotovoltaic unit.

In the seventh arrangement above, it is preferable that the photovoltaicunit is provided with a light receiving face that faces an end of thefluorescent emission layer as viewed in a planar direction (eightarrangement). Thus, if dichroic fluorescent pigment molecules aredisposed in the fluorescent emission layer such that the direction ofthe transition dipole moments is in agreement with a thickness directionof the fluorescent emission layer, light emitted from dichroicfluorescent pigment molecules can be efficiently received by thephotovoltaic unit. Thus, positioning the photovoltaic unit in the mannerdescribed above will allow the photovoltaic unit to generate electricityefficiently.

Preferred embodiments of the semiconductor device of the presentinvention will now be described with reference to the drawings. Itshould be noted that the sizes of the components in the drawings do notexactly represent the sizes of actual components or size ratios of thecomponents.

[First Embodiment]

(Overall Configuration)

FIG. 1 schematically shows a display panel 1 of a liquid crystal displaydevice (display device) according to a first embodiment. The displaypanel 1 includes an active matrix substrate 2, a counter substrate 3,and a liquid crystal layer 4 sandwiched therebetween.

The active matrix substrate 2 includes a substrate 11 including multiplepixels provided in a matrix. The active matrix substrate 2 also includespixel electrodes 12 and thin film transistors (hereinafter referred toas “TFTs”) corresponding to the pixels. The substrate 11 is made of atranslucent glass substrate, and the pixel electrodes 12 are made of atransparent conductive film. That is, in the present embodiment, theactive matrix substrate 2 is a transmissive substrate that allows lightto pass through it.

The counter substrate 3 includes a base substrate 21 made of glass, acommon electrode 22 opposite the pixel electrodes 12 of the activematrix substrate 2, and a fluorescent emission layer 23 having dichroicfluorescent pigment molecules 23 a. The fluorescent emission layer 23 isprovided between the base substrate 21 and the common electrode 22. Thatis, in the counter substrate 3, the common electrode 22 opposite thepixel electrodes 12 of the active matrix substrate 2, the fluorescentemission layer 23 and the base substrate 21 are stacked in this statedorder, beginning from the layer closest to the active matrix substrate2. Similar to the pixel electrodes 12 of the active matrix substrate 2,the common electrode 22 of the counter substrate 3 is made of atransparent conductive film. The structure of the fluorescent emissionlayer 23 will be described below.

The liquid crystal layer 4 is formed by dispersing liquid crystal in theshape of liquid crystal droplets 4 a in polymer matrix 4 b. That is, theliquid crystal display device of the present embodiment is a displaydevice including so-called polymer dispersed liquid crystal (hereinafterreferred to as “PDLL”).

In the liquid crystal layer 4, liquid crystal molecules in liquidcrystal droplets 4 a are randomly oriented (i.e. in a scattering state)when no voltage is applied between the pixel electrodes 12 and thecommon electrode 22. Thus, the polymer matrix 4 b and the liquid crystaldroplets 4 a have different refractive indices such that light isscattered at the interfaces therebetween.

When a voltage is applied between the pixel electrodes 12 and the commonelectrode 22, the liquid crystal molecules in the liquid crystaldroplets 4 a are oriented with their molecular axes aligned in apredetermined direction (i.e. in an oriented state). Thus, the polymermatrix 4 b and the liquid crystal droplets 4 a have substantially thesame refractive index, reducing scattering at the interfacestherebetween, thereby making the liquid crystal layer 4 transparent.

The liquid crystal display device is configured to apply a voltagebetween the pixel electrodes 12 and the common electrode 22 by drivingTFTs in the active matrix substrate 2 in response to signals from adriver provided on the active matrix substrate 2. The liquid crystaldisplay device is also configured to control liquid crystal in theliquid crystal layer 4 by means of such a voltage applied between thepixel electrodes 12 and the common electrode 22 to display an image onthe display panel 1.

(Fluorescent Emission Layer)

Next, the structure of the fluorescent emission layer 23 providedbetween the base substrate 21 and the common electrode 22 in the countersubstrate 3 will be described.

The fluorescent emission layer 23 includes dichroic fluorescent pigmentmolecules 23 a and liquid crystal polymer 23 b that holds the dichroicfluorescent pigment molecules 23 a. The dichroic fluorescent pigmentmolecules 23 a has an absorption band of an ultraviolet wavelengthregion (for example, 10 nm to 400 nm) and a visible light wavelengthregion (for example, 380 nm to 750 nm), and are made of a material witha dichroic ratio of 5 or more. The dichroic fluorescent pigmentmolecules 23 a are made of, for example, benzothiadiazole-based orcoumalin-, cyanine-, pyridine-, rhodamine-, styryl- oranthraquinone-based fluorescent pigment.

Dichroic fluorescent pigment molecules 23 a have the property ofabsorbing light such as ultraviolet or visible light and emitfluorescence. Dichroic fluorescent pigment molecules 23 a have theabsorption property of the absorption coefficient of light oscillatingin a direction parallel to their long molecular axis (i.e. light thatadvances in a direction perpendicular to their long molecular axis)being larger than the absorption coefficient of light oscillating in adirection perpendicular to their long molecular axis (i.e. light thatadvances parallel to their long molecular axis). In other words, thelong molecular axis of dichroic fluorescent pigment molecules 23 a ofthe present embodiment is in agreement with the direction of theirtransition moments for light absorption.

Further, the dichroic fluorescent pigment molecules 23 a have theemission property of the fluorescent emission coefficient in a directionparallel to their long molecular axis being larger than the fluorescentemission coefficient in a direction perpendicular to their longmolecular axis. In other words, the long molecular axis of the dichroicfluorescent pigment molecules 23 a of the present embodiment is inagreement with the direction of their transition moments for emission.Consequently, the dichroic fluorescent pigment molecules 23 a emitstronger light in a direction perpendicular to their long molecularaxis. In the drawings for the following description, the dichroicfluorescent pigment molecules 23 a are depicted as vertically longellipses, whose longitudinal direction corresponds to their longmolecular axis.

The liquid crystal polymer 23 b is made of a resin material that allowsthe dichroic fluorescent pigment molecules 23 a to be oriented such thattheir long molecular axis is in agreement with the direction of stackingof the layers (i.e. a thickness direction of the fluorescent emissionlayer 23), as shown in FIG. 1. Specifically, the liquid crystal polymer23 b is made of a compound having a photoreactive group at a moleculeend or a diacrylate compound having a liquid crystal framework. Itshould be noted that an ultraviolet absorbing material that absorbsultraviolet light may be mixed with the liquid crystal polymer 23 b.Thus, ultraviolet light passing through the fluorescent emission layer23 can be reduced in a more reliable manner, thereby protecting theliquid crystal layer 4 from ultraviolet light.

As discussed above, dichroic fluorescent pigment molecules 23 a may beheld in the fluorescent emission layer 23 by liquid crystal polymer 23 bto allow stronger light to be emitted from dichroic fluorescent pigmentmolecules 23 a in a direction perpendicular to the long molecular axisof the dichroic fluorescent pigment molecules 23 a, i.e. in a planardirection of the display panel 1. On the other hand, only weak light isemitted from dichroic fluorescent pigment molecules 23 a in a directionparallel to the long molecular axis of the dichroic fluorescent pigmentmolecules 23 a, i.e. a thickness direction of the fluorescent emissionlayer 23. Accordingly, as indicated by thin solid lines in FIGS. 2 and3, almost no light is emitted from dichroic fluorescent pigmentmolecules 23 a directly to the outside of the display panel 1.

As discussed above, each layer of the display panel 1 is made of atransparent material such that light emitted from dichroic fluorescentpigment molecules 23 a in a planar direction of the display panel 1 isreflected from an interface between the display panel 1 and air. Morespecifically, as shown in FIG. 2, when a voltage is applied to theliquid crystal layer 4 and the liquid crystal layer 4 is transparent,light emitted from dichroic fluorescent pigment molecules 23 a istotally reflected from the interface between the layer and air and isreflected repeatedly within the display panel 1 (see thick arrows).Light emitted from dichroic fluorescent pigment molecules 23 a at anincident angle relative to the interface between the layer and air thatis smaller than the total reflection angle is emitted to the outside.

On the contrary, as shown in FIG. 3, when no voltage is applied to theliquid crystal layer 4 and the liquid crystal layer 4 is in thescattering state, light emitted from dichroic fluorescent pigmentmolecules 23 a is scattered by the liquid crystal layer 4 and emitted tothe outside of the display panel 1 (see thick arrows). Moreover, aportion of light scattered by the liquid crystal layer 4 is reflectedwithin the display panel 1 and returns to dichroic fluorescent pigmentmolecules 23 a such that the amount of light absorbed by dichroicfluorescent pigment molecules 23 a is larger than is the case in FIG. 2.Thus, dichroic fluorescent pigment molecules 23 a emit brighter lightthan is the case in FIG. 2.

Further, as discussed above, dichroic fluorescent pigment molecules 23 aabsorb ultraviolet light. Thus, as discussed above, a fluorescentemission layer 23 provided on the side of the liquid crystal layer 4closer to the front side of the display panel 1 can reduce the amount ofultraviolet light reaching the liquid crystal layer 4.

It should be noted that the depiction of liquid droplets 4 a in theliquid crystal layer 4 is omitted in FIGS. 2 and 3 in order toillustrate the difference in the state of the liquid crystal layer 4between the two drawings clearly and in a simplified manner.

(Method of Manufacturing Display Panel)

Now, a method of manufacturing such a display panel will be described.

First, on a base substrate 21 is formed a fluorescent emission layer 23.The fluorescent emission layer 23 is formed by spin coating, forexample. Specifically, dichroic fluorescent pigment molecules 23 a areadded to the liquid crystal polymer 23 b, which is then stirred untilthe dichroic fluorescent pigment molecules 23 a are dissolved to make amixture. Then, to improve the wettability of the mixture with the basesubstrate 21, an oriented film is formed on the base substrate 21.Thereafter, the mixture is applied to the oriented film before the basesubstrate 21 is spun to coat the oriented film with the mixture to apredetermined thickness. After the resulting structure is heated toevaporate the solvent, it is illuminated with ultraviolet light to curethe liquid crystal polymer 23 b. Thus, a fluorescent emission layer 23is formed on the base substrate 21.

It should be noted that the mixture may be applied to the oriented filmby a slit coater, instead of by spin coating as discussed above.

Next, a common electrode 22 is formed on the fluorescent emission layer23 by sputtering, for example. Then, a spacer that is to be positionedbetween the common electrode 22 and an active matrix substrate 2 isprovided on the common electrode. Thus, a counter substrate 3 is formed.

Next, an oriented film is provided on each of the counter substrate 3and the active matrix substrate 2. Since the active matrix substrate 2may be manufactured in a conventional method, description of a method ofmanufacturing the active matrix substrate 2 will be omitted. A patternof seal of a light curing resin is formed on the counter substrate 3.Thereafter, droplets of a mixture of liquid crystal, polymer matrix 4 band other ingredients are applied to the counter substrate 3, which isthen attached to the active matrix substrate 2 in vacuum.

Thereafter, the pressure is returned to atmospheric pressure and, whenthe mixture described above is spread in the seal pattern, it isilluminated, from the side of the counter substrate 3, with ultravioletlight having wavelengths not higher than 340 nm removed. Thus, the sealresin is cured to produce PDLC. Thereafter, the counter substrate 3 andactive matrix substrate 2, as combined together, are baked to completelycure the seal.

Thus, a display panel 1 as shown in FIG. 1 is provided.

(Effects of First Embodiment)

In the present embodiment, a fluorescent emission layer 23 containingdichroic fluorescent pigment molecules 23 a is provided as a separatelayer from the liquid crystal layer 4. This makes it possible toincrease the thickness of the fluorescent emission layer 23 to providesufficient fluorescence without changing the voltage applied to theliquid crystal layer 4.

Moreover, as dichroic fluorescent pigment molecules 23 a are disposedsuch that their long molecular axis is parallel to a thickness directionof the fluorescent emission layer 12 in the fluorescent emission layer23, the display panel 1 can be switched between on and off offluorescence. Dichroic fluorescent pigment molecules 23 a emit stronglight in a direction perpendicular to their long molecular axis, whilethey emit weak light in a direction parallel to their long molecularaxis. Thus, as the dichroic fluorescent pigment molecules 23 a aredisposed as described above, almost no light is emitted from dichroicfluorescent pigment molecules 23 a directly to the outside of thedisplay panel 1. On the contrary, light emitted from dichroicfluorescent pigment molecules 23 a in a direction perpendicular to theirlong molecular axis is reflected within the display panel 1 and istrapped in the display panel 1 when the liquid crystal layer 4 is in thetransparent state; when the liquid crystal layer 4 is in the scatteringstate, such light is scattered in the liquid crystal layer 4 and is thenemitted to the outside of the display panel 1. Thus, fluorescence of thedisplay panel 1 can be controlled by controlling the liquid crystal inthe liquid crystal layer 4.

Further, since dichroic fluorescent pigment molecules 23 a absorbultraviolet light as well, the arrangement of the present embodiment canreduce the amount of ultraviolet light reaching the liquid crystal layer4.

(Variation 1 of First Embodiment)

As shown in FIG. 4, this variation is different from the firstembodiment in that ultraviolet absorbing films 25, 25 are placed on therespective sides of the display panel 1 shown in FIG. 1. In thedescription below, the components that are the same as those of thefirst embodiment are labeled with the same characters, and only thedifferences will be described.

Specifically, an ultraviolet absorbing film 25 is attached to the basesubstrate 21 of the counter substrate 3 by means of adhesive 26. Also,an ultraviolet absorbing film 25 is attached to the substrate 11 of theactive matrix substrate 2 by means of adhesive 26. These ultravioletabsorbing films 25, 25 are configured to block light with a wavelengthnot higher than 480 nm.

Thus, ultraviolet light can be prevented from reaching the liquidcrystal layer 4, thereby protecting the liquid crystal layer 4.

(Variation 2 of First Embodiment)

As shown in FIG. 5, this variation is different from the firstembodiment in that the active matrix substrate 30 is a reflectivesubstrate, not a transparent one. In the description below, thecomponents that are the same as those of the first embodiment arelabeled with the same characters, and only the differences will bedescribed.

Specifically, the active matrix substrate 30 includes a substrate 31having a reflective layer 31 a, a pixel electrode 32 formed on thesubstrate 31, and TFTs, not shown, also formed on the substrate 31.Thus, light entering the counter substrate 3 is reflected from thesubstrate 31.

Thus, light emitted from dichroic fluorescent pigment molecules 23 a ofthe fluorescent emission layer 23 is reflected from the substrate 31 ofthe active matrix substrate 30.

In this variation, an ultraviolet absorbing film 25 similar to that ofVariation 1 above is provided on the counter substrate 3, which allowslight to pass through it. The present variation is not limited to thisarrangement, and no ultraviolet absorbing film 25 may be provided.

[Second Embodiment]

FIG. 6 schematically shows a display panel 61 according to a secondembodiment. This embodiment is different from the first embodiment inthe configuration of the pixel electrode. The differences between thefirst and second embodiments will be mainly described.

Specifically, the display panel 61 includes an active matrix substrate62, a counter substrate 63 and a liquid crystal layer 64 sandwichedtherebetween.

The active matrix substrate 62 includes a substrate 71 with multiplepixels provided in a matrix. Further, a pectinate electrode 72 and TFTs(not shown) are provided on the active matrix substrate 62. Thesubstrate 71 is made of a translucent glass substrate, and the pectinateelectrode 72 is made of a transparent, conductive film. That is, in thepresent embodiment, the active matrix substrate 62 is a transparentsubstrate that allows light to pass through it.

The pectinate electrode 72 includes a plurality of line-shapedconductive members 72 a formed parallel to each other on the substrate71. In other words, the plurality of conductive members 72 a are formedas stripes. In the present embodiment, the pectinate electrode 72 isformed in such a way that those conductive members 72 a that function aspixel electrodes and those conductive members 72 a that function as acommon electrode are arranged in an alternating manner. Thus, as avoltage is applied to the liquid crystal layer 64 by the pectinateelectrode 72, the liquid crystal in the liquid crystal layer 64 iscontrolled by an electric field generated between the conductive members72 a.

The counter substrate 63 includes a base substrate 81 made of glass anda fluorescent emission layer 82 having dichroic fluorescent pigmentmolecules 82 a. The fluorescent emission layer 82 is provided on thebase substrate 81 so as to be positioned between the base substrate 81and the liquid crystal layer 64. In other words, in the countersubstrate 63, the fluorescent emission layer 82 and the base substrate81 are stacked in this stated order, beginning from the layer close tothe active matrix substrate 62. The structure of the fluorescentemission layer 82 is the same as that of the first embodiment, and itsdetailed description will be omitted. Character 82 b in FIG. 6 denotesliquid crystal polymer that holds the dichroic fluorescent pigmentmolecules 82 a.

The liquid crystal layer 64 is formed by dispersing liquid crystal inthe shape of liquid crystal droplets 64 a in the polymer matrix 64 b.The structure of the liquid crystal layer 64 is also the same as that ofthe first embodiment, and its detailed description will be omitted.

If a transparent common electrode is provided, as in the firstembodiment, the common electrode is generally formed from indium tinoxide (hereinafter referred to as “ITO”); however, ITO has a highrefractive index and has the property of absorbing visible light. Assuch, if a transparent common electrode is provided between thefluorescent emission layer and the liquid crystal layer, as in the firstembodiment, light emitted from dichroic fluorescent pigment of thefluorescent emission layer is reflected or absorbed by the commonelectrode and may not reach the liquid crystal layer.

On the contrary, if the electrode in the active matrix substrate 62 is apectinate electrode 72, described above, no common electrode isnecessary on the counter substrate 63. Thus, no light is reflected orabsorbed by a common electrode of ITO, as discussed above, such thatlight emitted from dichroic fluorescent pigment 82 a of the fluorescentemission layer 82 can be efficiently passed to the liquid crystal layer64.

The active matrix substrate 62 may be a reflective substrate. In thiscase, a surface of the substrate 71 of the active matrix substrate 62constitutes a reflective surface, where light entering the countersubstrate 63 or light emitted from dichroic fluorescent pigmentmolecules 82 a of the fluorescent emission layer 82 is reflected fromthe substrate 71.

Although not shown, an ultraviolet absorbing film may be attached toeach side of the display panel 61, as in Variation 1 of the firstembodiment.

(Method of Manufacturing Display Panel)

Next, a method of manufacturing a display panel 61 will be described.

First, on a base substrate 81 is formed a fluorescent emission layer 82.As in the first embodiment, the fluorescent emission layer 82 is formedby spin coating, for example. Specifically, dichroic fluorescent pigmentmolecules 82 a are added to the liquid crystal polymer 82 b, which isthen stirred until the dichroic fluorescent pigment molecules 82 a aredissolved to make a mixture. Then, to improve the wettability of themixture with the base substrate 81, an oriented film is formed on thebase substrate 81. Thereafter, the mixture is applied to the orientedfilm before the base substrate 81 is spun to coat the oriented film withthe mixture to a predetermined thickness. After the resulting structureis heated to evaporate the solvent, it is illuminated with ultravioletlight to cure the liquid crystal polymer 82 b. Thus, a fluorescentemission layer 82 is formed on the base substrate 81. A spacer that isto be positioned between the fluorescent emission layer 82 and an activematrix substrate 62 is provided on the layer. Thus, a counter substrate63 is formed.

It should be noted that the mixture may be applied to the oriented filmby a slit coater, instead of by spin coating as discussed above.

Next, an oriented film is provided on each of the counter substrate 63and the active matrix substrate 62. A pectinate electrode 72 and TFTsare formed on the active matrix substrate 62. Since these components maybe manufactured in a conventional method of forming electrodes and TFTs,their detailed description will be omitted. A pattern of seal of a lightcuring resin is formed on the counter substrate 63. Thereafter, dropletsof a mixture of liquid crystal, polymer matrix 64 b and otheringredients are applied to the counter substrate 63, which is thenattached to the active matrix substrate 62 in vacuum.

The pressure is returned to atmospheric pressure and, when the mixturedescribed above is spread in the seal pattern, it is illuminated, fromthe side of the counter substrate 63, with ultraviolet light havingwavelengths not higher than 340 nm removed. Thus, the seal resin iscured to produce PDLC. Thereafter, the counter substrate 3 and activematrix substrate 2, as combined together, are baked to completely curethe seal.

Thus, a display panel 61 as shown in FIG. 6 is provided.

(Effects of Second Embodiment)

The arrangement of the present embodiment provides effects similar tothose of the first embodiment discussed above.

Further, in the present embodiment, the pixel electrodes and commonelectrode are replaced by a pectinate electrode 72 having linearconductive members 72 a that function as pixel electrodes and a commonelectrode. Thus, no transparent common electrode between the fluorescentemission layer 82 and liquid crystal layer 64 is necessary. As such,light emitted from dichroic fluorescent pigment molecules 82 a of thefluorescent emission layer 82 can be prevented from being reflected orabsorbed by a transparent common electrode made of ITO or the like.Thus, light emitted from dichroic fluorescent pigment molecules 82 a canbe efficiently passed to the liquid crystal layer 64 and scattered bythe liquid crystal layer 64. This allows the display panel 61 to emitbrighter fluorescence.

[Third Embodiment]

FIG. 7 schematically illustrates a display panel 41 according to a thirdembodiment. This embodiment is different from the first and secondembodiments in the configuration of the common electrode. In thefollowing description, the components that are the same as those of thefirst embodiment are labeled with the same characters, and thedifferences between the first and third embodiments will be mainlydescribed.

Specifically, as shown in FIG. 7, the counter substrate 42 includes abase substrate 43 and a common electrode 44 formed on the base substrate43. An ultraviolet absorbing film 25 is attached, by adhesive 26, to theside of the base substrate 43 opposite the side with the commonelectrode 44. Further, a fluorescent pigment film 45 is attached to theultraviolet absorbing film 25 by adhesive 46. The fluorescent pigmentfilm 45 is a fluorescent emission layer 23 of the first embodiment thatis shaped as a film. That is, a light emitting layer 45 c havingdichroic fluorescent pigment molecules 45 a oriented in such a way thattheir long molecular axis is in agreement with a thickness direction ofthe film is provided on a base film 45 b that does not absorbultraviolet light. The adhesive 46 forms a bond layer and theultraviolet absorbing film 25 corresponds to the bonded portion. Theultraviolet absorbing film 25 forms an ultraviolet absorbing layer.

The above arrangement allows the fluorescent pigment film 45 toefficiently absorb ultraviolet light. Moreover, ultraviolet light notabsorbed by the fluorescent pigment film 45 can be absorbed by theultraviolet absorbing film 25.

The above features can alternatively be applied to the secondembodiment. An implementation with the arrangement applied to the secondembodiment is shown in FIG. 8. If the arrangement is applied to thesecond embodiment, no common electrode 44 is necessary.

(Effects of Third Embodiment)

In the present embodiment, an ultraviolet absorbing film 25 is attachedto the side of the base substrate 43 of the counter substrate 42opposite the side with the common electrode 44, and a fluorescentpigment film 45 is attached to the ultraviolet absorbing film 25. Thus,since the fluorescent pigment film 45 is located on the top surface ofthe display panel 41, ultraviolet light can be efficiently absorbed bythe fluorescent pigment film 45 to allow the fluorescent pigment film 45to emit stronger fluorescence. Moreover, since ultraviolet light thathas passed through the fluorescent pigment film 45 can be absorbed bythe ultraviolet absorbing film 25, ultraviolet light can be preventedfrom reaching the liquid crystal layer 4. Thus, the liquid crystal layer4 can also be protected.

Further, as the fluorescent emission layer is a fluorescent pigment film45, as discussed above, a fluorescent emission layer can be easilyformed on the counter substrate 42.

Furthermore, the fluorescent pigment film 45 described above makes itpossible to form a fluorescent emission layer after forming a liquidcrystal layer 4. During formation of a liquid crystal layer 4, thecounter substrate 42 is illuminated with ultraviolet light havingwavelengths not higher than 340 nm removed, as discussed above inconnection with the first embodiment; as a fluorescent pigment film 45as described above is to be used, no member absorbing ultraviolet lightis present in the counter substrate 42. Thus, during formation of aliquid crystal layer 4, the liquid crystal layer 4 can be efficientlyilluminated with ultraviolet light.

(Variation of Third Embodiment)

As shown in FIG. 9, this variation is different from the thirdembodiment in the structure of the fluorescent pigment film 51. In thedescription below, the components that are the same as those of thethird embodiment are labeled with the same characters and only thedifferences will be described.

Specifically, the fluorescent pigment film 51 includes a base film 51 bthat absorbs almost no ultraviolet light, a light emitting layer 51 cwith dichroic fluorescent pigment molecules 51 a, and a bonding layer 51d provided on the side of the fluorescent emission layer 51 b oppositethe side with the base film 51 b. The adhesive forming this bondinglayer 51 d includes an ultraviolet absorbing agent mixed with it thatcan absorb light with wavelengths not higher than 480 nm (mainlyultraviolet light). The ultraviolet absorbing agent may be abenzotriazole- or benzophenone-based ultraviolet absorbing agent. Thus,this adhesive forms an ultraviolet absorbing layer. The base substrate43 corresponds to the bonded portion.

This will eliminate the necessity to provide an ultraviolet absorbingfilm 26, as in the third embodiment, thereby simplifying themanufacturing process.

It should be noted that an ultraviolet absorbing agent may be introducedinto the fluorescent emission layer 51 b instead of the adhesive agent.This will allow the fluorescent emission layer 51 b to absorb almost allultraviolet light.

The above features can alternatively be applied to the arrangement ofFIG. 8.

Further, in the arrangement of FIG. 9, the light emitting layer 51 c andthe base film 51 b may be interchanged. In this case, a bonding layer 51d is provided on the side of the base film 51 b opposite the side withthe light emitting layer 51 c. In this arrangement, an ultravioletabsorbing agent may be suitably introduced into one of the base film 51b and the bonding layer 51 d.

[Fourth Embodiment]

FIG. 10 schematically shows a display panel 91 according to a fourthembodiment. This embodiment is different from the first embodiment in alight guide plate 95 provided on the fluorescent emission layer 113. Thedifferences between the first and fourth embodiments will be mainlydescribed below.

Specifically, the display panel 91 includes an active matrix substrate92, a counter substrate 93, a liquid crystal layer 94 sandwichedtherebetween, and a light guide plate 95.

The active matrix substrate 92 includes a substrate 101 with multiplepixels provided in a matrix. Pixel electrodes 102 and TFTs (not shown)corresponding to the pixels are also provided on the active matrixsubstrate 92. A reflective layer 101 a is provided on a surface of thesubstrate 101, and the pixel electrodes 102 are also configured toreflect light. That is, in the present embodiment, the active matrixsubstrate 92 is a reflective substrate that reflects light.

The counter substrate 93 includes a base substrate 111 made of glass, acommon electrode 112 that faces the pixel electrodes 102 of the activematrix substrate 92, and a fluorescent emission layer 113 with dichroicfluorescent pigment molecules 113 a. The fluorescent emission layer 113is bonded, by an adhesive 114, to the side of the base substrate 111opposite the side with the common electrode 112. In other words, in thecounter substrate 93, the common electrode 112 that faces the pixelelectrodes 102 of the active matrix substrate 92, the base substrate 111and the fluorescent emission layer 113 are stacked in this stated order,beginning from the layer close to the active matrix substrate 92.Similar to the pixel electrodes 102 of the active matrix substrate 92,the common electrode 112 of the counter substrate 93 is made of atransparent conductive film. The structure of the fluorescent emissionlayer 113 is the same as that of the first embodiment, and its detaileddescription will be omitted.

An ultraviolet absorbing agent is added to the adhesive 114 between thefluorescent emission layer 113 and the base substrate 111. Thus, theultraviolet absorbing agent in the adhesive 114 can absorb light withwavelengths not higher than 480 nm (mainly ultraviolet light), therebypreventing the liquid crystal layer 94 from being illuminated withultraviolet light. That is, the adhesive 114 forms the ultravioletabsorbing layer.

The liquid crystal layer 94 is formed by dispersing liquid crystal inthe shape of liquid crystal droplets 94 a in the polymer matrix 94 b.The structure of the liquid crystal layer 94 is also similar to that ofthe first embodiment and its detailed description will be omitted.

The light guide plate 95 is a transparent member that does not absorbultraviolet light and is made of an acrylic material or polycarbonate,for example, and is configured to guide light from a light source 96,such as an LED, to the fluorescent emission layer 113. That is, lightfrom the light source 96 is reflected in the light guide plate 95 and isguided to the fluorescent emission layer 113. Thus, as shown in FIG. 10,light enters dichroic fluorescent pigment molecules 113 a of thefluorescent emission layer 113 in a direction perpendicular to theirlong molecular axis. Thus, dichroic fluorescent pigment molecules 113 aemit stronger fluorescence than in the case when light enters in adirection parallel to the long molecular axis of the dichroicfluorescent pigment molecules 113 a.

The light source 96 is a source of light with wavelengths includingphotoexcitation wavelengths for the dichroic fluorescent pigmentmolecules 113 a. The light source 96 is preferably an LED that emitsultraviolet light, for example. Such a light source 96 will allowdichroic fluorescent pigment molecules 113 a to emit brighterfluorescence.

A reflective plate 97 is provided on the end of the light guide plate 95opposite the end with the light source 96. The reflective plate 97reflects light that has advanced to this end of the light guide plate 95to return it back to the light guide plate 95.

The light guide plate 95, fluorescent emission layer 113 and basesubstrate 111 are bonded together such that propagation of light is notprevented.

(Effects of Fourth Embodiment)

In the present embodiment, a light guide plate 95 is provided on thefluorescent emission layer 113 for guiding light from the light source96 to the fluorescent emission layer 113. Thus, light enters dichroicfluorescent pigment molecules 113 a in the fluorescent emission layer113 in a direction perpendicular to the long molecular axis of thedichroic fluorescent pigment molecules 113 a such that dichroicfluorescent pigment molecules 113 a emit brighter fluorescence.

Further, using an LED that emits ultraviolet light as a light source 96will allow dichroic fluorescent pigment molecules 113 a to emit yetbrighter fluorescence.

[Fifth Embodiment]

FIG. 11 schematically illustrates a display device 121 according to afifth embodiment. This embodiment illustrates an implementation in whichthe display panel 91 of the fourth embodiment is combined with solarcells. In the description below, the components that are the same asthose of the fourth embodiment are labeled with the same characters, andonly the differences will be described.

As shown in FIG. 11, the display device 121 includes a display panel 91located in an opening 120 a of a housing 120 of a cellular phone, forexample, and solar cells 131 (which constitute a light generating unit)located at sides of the display panel 91. The display panel 91 has thesame configuration as that of the fourth embodiment, where the lightguide plate 95 is located in the housing 120 such that the plate isexposed at the opening 120 a of the housing 120. The display panel 91 islocated in the housing 120 such that the active matrix substrate 92 andthe counter substrate 93 are positioned at the opening 120 a of thehousing 120 as viewed in a planar view.

The light guide plate 95 of the display panel 91 is generally shaped asa rectangle as viewed in a planar view, and two light sources 96, 96 areprovided on one end thereof as viewed in a longitudinal direction, and areflective plate 97 is provided on the other end thereof. Solar cells131, 131 are located at the two sides of the light guide plate 95 of thedisplay panel 91 as viewed in a lateral direction.

As shown in FIG. 12 in a cross section, each of the solar cells 131 islocated such that its electricity generating surface 131 a (lightreceiving surface) that receives light and generates electricity facesan end of the display panel 91 as viewed in a planar direction. Thus,light emitted from dichroic fluorescent pigment molecules 113 a of thefluorescent emission layer 113 in a direction perpendicular to theirlong molecular axis can be received by the electricity generatingsurface 131 a of the solar cell 131. Dichroic fluorescent pigmentmolecules 113 a emit stronger fluorescence in a direction perpendicularto their long molecular axis (i.e. the direction of the hollow arrow inthe drawing). Thus, the electricity generating surfaces 131 a of thesolar cells 131 can receive stronger light emitted from dichroicfluorescent pigment molecules 113 a. Thus, the solar cells 131 canefficiently generate electricity.

The solar cells 131 are spaced apart from the light guide plate 95. Ifthe solar cells 131 were closely attached to the light guide plate 95,light supposed to be transmitted to the light guide plate 95 would beabsorbed by the solar cells 131. On the contrary, as the solar cells 131are spaced apart from the light guide 95, as discussed above, it ispossible to avoid the solar cells 131 preventing light from beingpropagated in the light guide plate 95.

(Effects of Fifth Embodiment)

In the present embodiment, solar cells 131, 131 are located at sides ofthe display panel 91. Thus, fluorescent light emitted from dichroicfluorescent pigment molecules 113 a in the fluorescent emission layer113 of the display panel 91 can be received by the solar cells 131 togenerate electricity.

Moreover, as each of the solar cells 131 has an electricity generatingsurface 131 a facing an end of the display panel 91 as viewed in aplanar direction, the electricity generating surfaces 131 a canefficiently receive light from dichroic fluorescent pigment molecules113 a. Further, the dichroic fluorescent pigment molecules 113 a arelocated such that their long molecular axis is in agreement with adirection of stacking of the layers of the display panel 91 such thatstronger fluorescent light emitted in a direction perpendicular to theirlong molecular axis exits to the outside of the display panel 91 asviewed in a planar direction. Thus, solar cells 131 with theirelectricity generating surfaces 131 a facing the ends of the displaypanel 91 as viewed in a planar direction can generate electricity moreefficiently.

Furthermore, locating the solar cells 131 as described above willprevent solar light from directly entering the electricity generatingsurface 131 a of a solar cell 131, thereby preventing the temperature ofthe solar cells 131 from rising. This will prevent decrease in powergeneration efficiency due to a rise in temperature of the solar cells131.

[Other Embodiments]

While the embodiments of the present invention have been described, theabove embodiments are merely examples that can be used to carry out thepresent invention. Thus, the present invention is not limited to theabove embodiments, and the above embodiments may be modified asnecessary without departing from the spirit of the invention.

In the above embodiments, PDLC is used for the liquid crystal layer.However, polymer network liquid crystal (PNLC), which includes polymerformed in the shape of a network between two plastic films in whichliquid crystal molecules are provided may be used for the liquid crystallayer.

In the above embodiments, dichroic fluorescent pigment molecules withtheir long molecular axis parallel to the direction of their transitiondipole moments are used. However, dichroic fluorescent pigment moleculeswith their short molecular axis parallel to that of their transitiondipole moments may be used. In this case, too, the dichroic fluorescentpigment molecules in the fluorescent emission layer may be suitablyoriented such that the direction of their transition dipole moments isin agreement with a thickness direction of the fluorescent emissionlayer.

In the above embodiments, the dichroic fluorescent pigment molecules inthe fluorescent emission layer are oriented such that the direction oftheir transition dipole moments is in agreement with a thicknessdirection of the fluorescent emission layer. However, the dichroicfluorescent pigment molecules may be oriented in any other directions aslong as each molecule has a transition dipole moment with the samedirection.

In the above embodiments, the display panel is of a monochromeconfiguration. However, the display panel may be a display panel capableof multicolor display, such as tricolor. In this case, the dichroicfluorescent pigment molecules in the fluorescent emission layer arepreferably oriented such that their long molecular axis (i.e. thedirection of their transition dipole moments) is in agreement with aplanar direction of the display panel and the direction in which thepixels of the three colors are arranged. Thus, stronger light emittedfrom dichroic fluorescent pigment molecules in a direction perpendicularto their long molecular axis is emitted into the pixels of thecorresponding color, thereby preventing it from being mixed with otherpixel colors or preventing light from being absorbed by dichroicfluorescent pigment molecules in pixels for other colors, providingimproved display quality. Here, the dichroic fluorescent pigmentmolecules of three colors, i.e. blue, green and red, must be providedand the pixels for the three colors must be formed in the fluorescentemission layer. Further, if a pectinate electrode as in the secondembodiment is used, the conductive members of the pectinate electrodeare preferably parallel to the long molecular axis (i.e. the directionof their transition dipole moments) of the dichroic fluorescent pigmentmolecules. However, the conductive members may be at an angle of 45degrees or less relative to the long molecular axis (i.e. the directionof their transition dipole moments) of the dichroic fluorescent pigmentmolecules.

A tricolor fluorescent emission layer as described above may bemanufactured by spin coating or ink jet methods. Specific examples ofthese methods are as follows.

In spin coating, first, blue, green and red dichroic fluorescent pigmentmolecules are added to liquid crystal polymer to prepare blue, green andred mixtures. A black matrix is formed on the substrate usingpatterning. Then, an oriented film is applied to the substrate beforethe mixture of one of the colors is applied to the oriented film by spincoating. The resulting structure is dried to evaporate the solventbefore the portions of the other two colors are covered with a mask andilluminated with ultraviolet light to cure the liquid crystal polymer.Then, the uncured portions are washed. This process is performed for theother two colors in a similar manner. This results in a tricolorfluorescent emission layer. It should be noted that spin coating may bereplaced by slit coating.

Similarly, in an ink jet method, blue, green and red dichroicfluorescent pigment molecules are first added to liquid crystal polymerto prepare blue, green and red mixtures. A water-repellent black matrixis formed on the substrate. Then, an oriented film is applied to thesubstrate before the mixture of one of the above colors is applied tothe desired pixels by an ink jet method. The resulting structure isdried to evaporate the solvent before it is illuminated with ultravioletlight to cure the liquid crystal polymer. This process is performed forthe other two colors in a similar manner. This results in a tricolorfluorescent emission layer.

In the second embodiment, the conductive members 72 a of the pectinateelectrode 72 function as pixel electrodes and a common electrode.However, an entire pectinate electrode may be used as pixel electrodeswhile an electrode laminated over the entire surface of the pectinateelectrode with an interposed insulating member may function as a commonelectrode. In this case, an electric field generated between thepectinate electrode and the electrode provided over its entire surfacecontrols liquid crystal in the liquid crystal layer 64.

INDUSTRIAL APPLICABILITY

The display device according to the present invention can be used as adisplay device capable of emitting fluorescence.

The invention claimed is:
 1. A display device comprising: a fluorescentemission layer comprising fluorescent pigment molecules that absorblight to emit fluorescence; a liquid crystal layer capable of switchingbetween a transparent state and a scattering state; a pair of electrodesprovided so as to sandwich the liquid crystal layer; and a color filterincluding pixels of multiple colors: wherein the fluorescent pigmentmolecules are dichroic fluorescent pigment molecules with differentemission intensities depending on a direction of emission, the dichroicfluorescent pigment molecules in the fluorescent emission layer areoriented such that a direction of transition dipole moments is inagreement with a planar direction of the display device and a directionin which the pixels of the multiple colors are arranged, and thefluorescent emission layer is positioned outside the liquid crystallayer.
 2. The display device according to claim 1, wherein: thefluorescent emission layer includes a light emitting layer formed as asheet and a bonding layer that bonds the light emitting layer to abonded portion, and an ultraviolet absorbing agent is added to at leastone of the light emitting layer and the bonding layer.
 3. The displaydevice according to claim 1, wherein a light guide plate for introducinglight from a light source into the fluorescent emission layer isprovided on the fluorescent emission layer.
 4. The display deviceaccording to claim 1, further comprising: ultraviolet absorbing layersthat are placed on respective sides of the display panel.
 5. The displaydevice according to claim 1, further comprising: an active matrixsubstrate and a counter substrate on which the pair of electrodes areprovided respectively; wherein the active matrix substrate includes areflective layer.
 6. The display device according to claim 1, furthercomprising: an active matrix substrate and a counter substrate on whichthe pair of electrodes are provided respectively; wherein thefluorescent emission layer is provided on the counter substrate on anopposite side of the liquid crystal layer; and an ultraviolet absorbinglayer is provided between the counter substrate and the fluorescentemission layer.